package com.itheima.filter;

import com.itheima.utils.CurrentHolder;
import com.itheima.utils.JwtUtils;
import io.jsonwebtoken.Claims;
import jakarta.servlet.*;
import jakarta.servlet.annotation.WebFilter;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;

import java.io.IOException;

@Slf4j
@WebFilter(urlPatterns = "/*") // 拦截所有请求
public class TokenFilter implements Filter
{
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest; // 强转
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        // 1.获取到请求的路径
        String requestURI = request.getRequestURI(); // URI指示具体资源，如：/emp

        // 2.判断是否是登录请求，如果路径中包含 /login ，说明是登录请求，放行
        if (requestURI.contains("/login")){
            log.info("登录请求，放行");
            filterChain.doFilter(request, response);
            return;
        }

        // 3.获取请求头中的token
        String token = request.getHeader("token");

        // 4.判断token是否存在，如果不存在，说明用户没有登录，返回错误信息(响应401状态码)
        if (token == null || token.isEmpty()){
            log.info("令牌为空，响应401");
            response.setStatus(401);
            return;
        }

        // 5.如果token存在，校验令牌，如果校验失败 -> 返回错误信息(响应401状态码)
        try {
            Claims claims = JwtUtils.parseToken(token);
            Integer empId = Integer.valueOf(claims.get("id").toString());
            CurrentHolder.setCurrentId(empId); // 存入
            log.info("当前登录员工ID：{},将其存入ThreadLocal", empId);
        } catch (Exception e) {
            log.info("令牌非法，响应401");
            response.setStatus(401);
            return;
        }

        // 6.令牌校验成功，放行
        log.info("令牌合法，放行");
        filterChain.doFilter(request, response);

        // 7.删除ThreadLocal中的数据（放行后再删除）
        CurrentHolder.remove();
    }
}
